Raman fingerprints on the Bloch sphere of a spinor Bose-Einstein condensate

We explore the geometric interpretation of a diabatic, two-photon Raman process as a rotation on the Bloch sphere for a pseudo-spin-1/2 system. The spin state of a spin-1/2 quantum system can be described by a point on the surface of the Bloch sphere, and its evolution during a Raman pulse is a trajectory on the sphere determined by properties of the optical beams: the pulse area, the relative intensities and phases, and the relative frequencies. We experimentally demonstrate key features of this model with a $^{87}$Rb spinor Bose-Einstein condensate, which allows us to examine spatially dependent signatures of the Raman beams. The two-photon detuning allows us to precisely control the spin density and imprinted relative phase profiles, as we show with a coreless vortex. With this comprehensive understanding and intuitive geometric interpretation, we use the Raman process to create and tailor as well as study and characterize exotic topological spin textures in spinor BECs.Comment: 13 pages, 13 figures, submitted to the Journal of Modern Optics "20 Years of Bose-Einstein condensates" Special Issu

XY Spin Fluid in an External Magnetic Field

A method of integral equations is developed to study inhomogeneous fluids with planar spins in an external field. As a result, the calculations for these systems appear to be no more difficult than those for ordinary homogeneous liquids. The approach proposed is applied to the ferromagnetic XY spin fluid in a magnetic field using a soft mean spherical closure and the Born-Green-Yvon equation. This provides an accurate reproduction of the complicated phase diagram behavior obtained by cumbersome Gibbs ensemble simulation and multiple histogram reweighting techniques.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Preliminary Results of American Eel Sampling Efforts in Gulf of Mexico Drainages of Texas

American Eel Anguilla rostrata has a unique and complex life history that is fairly well-studied on the eastern coast of the United States, but few studies have been done on Gulf of Mexico drainages. To inform conservation and management decisions, efforts to better understand the population structure, seasonal dynamics, and life history of American Eel are underway. The primary objectives of our efforts are to assess the current and historical distribution and abundance, habitat use, movement patterns, parasite occurrence, diet and population structure of American Eel across all life stages in Gulf of Mexico drainages of Texas.Texas State Wildlife Grant Program grants T-173-R-1 and T-172-R-1 in cooperation with the U.S. Fish and Wildlife Service, Wildlife and Sport Fish Restoration ProgramIntegrative Biolog

Identifying consequences of cultural influence in international research projects by brazilian professors in The United States.

Identificar e avaliar a influência de fatores culturais em pesquisas desenvolvidas por meio de projetos internacionais é um tópico que está se tornando cada vez mais relevante à medida que o mundo continua a se globalizar. Valores culturais que diferem em todo o mundo influenciam a vida cotidiana muito mais do que muitas pessoas normalmente percebem. A contribuição científica deste trabalho está alinhada com outras publicações encontradas na área de gestão de projetos internacionais que abordam fatores culturais. Seu objetivo é identificar os fatores culturais e analisar sua influência no desenvolvimento de projetos de pesquisa internacionais. Tem como objeto de estudo onze professores, que realizaram projetos de pesquisas nos Estados Unidos. Como resultado se espera implementar medidas que preparem melhor os indivíduos para o desenvolvimento de seus projetos de pesquisas no exterior potencializando maximizar sua produtividade. O país mais comum estudado no contexto do desenvolvimento de projetos interculturais é a China. Foram identificados como fatores: total work and space (work orientation; participation in decisions; interaction with team); adapation (safety; laws and rules; politics / bureaucracy; religion; climate; distance from family); adaptation (social life; alimentation; communication); total work and space (development of new skills; workload; reception by team). Os fatores foram avaliados, pelos entrevistados, por meio de perguntas abertas e fechadas. Os resultados, condizentes com boa parte da literatura consultada, demonstraram que os fatores de maior importância para os brasileiros que desenvolveram projetos de pesquisa nos EUA são: a comunicação, o conforto no dia a dia, a vida social, e a autonomia no trabalho

New mean field theories for the liquid-vapor transition of charged hard spheres

The phase behavior of the primitive model of electrolytes is studied in the framework of various mean field approximations obtained recently by means of methods pertaining to statistical field theory (CAILLOL, J.-M., 2004, \textit{J. Stat. Phys.}, \textbf{115}, 1461). The role of the regularization of the Coulomb potential at short distances is discussed in details and the link with more traditional approximations of the theory of liquids is discussed. The values computed for the critical temperatures, chemical potentials, and densities are compared with available Monte Carlo data and other theoretical predictions.Comment: 17 pages, 4 figures, 3 table

Exact Renormalization Group : A New Method for Blocking the Action

We consider the exact renormalization group for a non-canonical scalar field theory in which the field is coupled to the external source in a special non linear way. The Wilsonian action and the average effective action are then simply related by a Legendre transformation up to a trivial quadratic form. An exact mapping between canonical and non-canonical theories is obtained as well as the relations between their flows. An application to the theory of liquids is sketched

Hunting for ecological indicators: are large herbivore skeleton measures from harvest data useful proxies for monitoring?

Hunter-collected data and samples are used as indices of population performance, and monitoring programs often take advantage of such data as ecological indicators. Here, we establish the relationships between measures of skeleton size (lower jawbone length and hind-leg length) and autumn carcass mass of slaughtered individuals of known age and sex of the high Arctic and endemic Svalbard reindeer (Rangifer tarandus platyrhynchus). We assess these relationships using a long-term monitoring dataset derived from hunted or culled reindeer. The two skeleton measures were generally strongly correlated within age class. Both jaw length (R2 = 0.78) and hind-leg length (R2 = 0.74) represented good proxies of carcass mass. These relationships were primarily due to an age effect (i.e. due to growth) as the skeleton measures reached an asymptotic size at 4–6 years of age. Accordingly, strong positive correlations between skeleton measures and carcass mass were mainly evident at the young age classes (range r [0.45–0.84] for calves and yearlings). For the adults, these relationships weakened due to skeletal growth ceasing in mature animals causing increased variance in mass with age—potentially due to the expected substantial impacts of annual environmental fluctuations. As proxies for carcass mass, skeleton measurements should therefore be limited to young individuals. Although body mass is the ‘gold standard’ in monitoring large herbivores, our results indicate that skeleton measures collected by hunters only provide similar valuable information for young age classes, particularly calves and yearlings. In sum, jaw length and hind-leg length function as proxies identical to body mass when documenting the impacts of changing environmental conditions on important state variables for reindeer and other herbivores inhabiting highly variable environments. Arctic · Citizen science · Hunter-collected data · Life history · Terrestrial large herbivoreHunting for ecological indicators: are large herbivore skeleton measures from harvest data useful proxies for monitoring?publishedVersio

Designing Authentic Cybersecurity Learning Experiences: Lessons from the Cybermatics Playable Case Study

This paper reports our work on an educational simulation that we call the Playable Case Study (PCS). A PCS is characterized by a fictitious narrative integrated with real-world learning activities, helping students learn skills, knowledge, and dispositions relevant to a professional career. We describe a recent pilot test of a PCS focused on the discipline of cybersecurity, emphasizing the kinds of tensions and difficulties that can arise during the development of immersive, experiential learning experiences: a) challenges accompanying the work of interdisciplinary PCS teams, particularly maintaining technical accuracy while still developing an authentic and engaging narrative; b) reconciling the opportunities provided by the philosophy of the simulation with the need to scaffold educational experiences to support students’ capabilities; and c) integrating the PCS into the classroom environment. We also provide design recommendations, in the form of questions that others can consider if they are attempting to create similar educational experiences